Hydraulic invalid-lifter.



v T SMITH. I HYDRAULIC INVALID LIFTER.

APPLICATION FILED AUG. 14, 19 09.

Patented Nov. 22, 1910.

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. THOMAS MARSHALL SMITH, OF- BALTIMORE, MARYLAND.

HYDRAULIC INVALID-LIFTER. v

976,307, Specification of Letters Patent. Patented NOV, 22, 191(1),

' Application filed. August 14, 1909. Serial No. 512,872. I

To all whom it may concern: the cylinder F back into the reservoir 80, Be it 'known that I, THOMAS MAnsuALL and by operating this knob, the lowering of SMITH, citizen of the United States, residing the plunger B, with the lifting apparatus at Baltimore, Maryland, have invented cercarrying the patient, can be controlled to a 60 tain new and useful Improvements in I-Iynicety, there being a succession of pressures draulic Invalid-Lifters, of which the followon the said knob, or by a continuous pressure in'g isa specification. which will open the valve 82 just to-the re- My invention relates to the general form quired degree to secure a gentle, falling of invalid lifters'disclosed by me in applimovement ofthe plunger'B. I provide a 65 cation for Letters Patent of the United safety port at 80- which, when the plungerB States No; 480972, renewed March 2, 1909, v has been raised to its upper limit, will allow and it consists in the features and combinathe oil to pass from the cylinder F back to tipn and arrangement of parts hereinafter the reservoir 30, so that further operation of "described and particularly pointed out in the appended claims.

In the accompanying drawings, Figurel is a plan view of a portion of the apparatus; Fig. 2' is a rear view with parts-in section,

the pump after the plungerhas attainedits maxnnum height will result only in the flow of the oil as just described, without further elevating the plunger B. It will be seen that the operating rod for the valve 82 is inclosed in a casing, and that the relief port '80 connectswith this casing. so that the oil can return through the casing from the port to the reservoir.

I claim as my invention l. In combination in an invalid lifter, a base, a cylinder, a plunger or standard mov able vertically therein, and a pump suspended Within the base, including a cylinder axiallyin line with the standard, a piston working within the said axial cylinder, and arr operating lever connected with the lower end of. the piston, substantially as described.

2. In combination with the base, a cylinand Fig. 3 a sectional elevation. 20 The machine comprises a central stand 'ard or plunger B movable vertically within a cylinder F. The base of the apparatus A is supported upon main carrying wheels 60 journaled on across shaft 61 mounted in the 25 base and by folding legs 32 having, at their outer ends, caster wheels 31*.

.For raising and lowering theplunger ,B, I employ a hydraulic-pump carried'by ,a block 26 which is suspended within the base 30 by having its flange bolted at 27 to the upper flange of the base casting. This suspended block has formed therewith a cylinder 74 in which a pump. piston 73 moves vertically, der extending .out therefrom, the plunger and axiallyin respect to the plunger B and movable in the cylinder, a block attached 35 below-t esame. The pump piston is operto the base and supporting the lower end ated by a foot lever 72 pivoted on the cross t of the cylinder, a cylinder carried by the shaft 61, and by a spring 79 surrounding a block axially below the upper cylinder, a rod 78 connected with the foot lever and piston movable in the lower cylinder, means bearing against abracket secured to the base. for operating the piston, and valve ports L0 When the foot lever is pressed downwardly, I leading to and from the cylinder, substanthe piston 73 is raised, forcing oil-from the tially as described. cylinder 74 past a valve 77 into the lower 3. In combination with the base, the cylend of the"'cylinder F, and against the piston inder extending up therefrom, a plunger 28 connected with the plunger B, and when movable vertically within the cylinder, at the pump piston 73 lowers, a freslrcharge of pump for elevating the plunger having its oil passes into the cylinder 74 from the rescylinder axially in line and below the cylervoir30 past the valve 76, and through the inder first mentioned, a piston working port 75. The reservoir 30 is arranged above within the lower cylinder, a lever connected the base, and is bolted thereto with the flange with the lower endof the piston, and a 0 of the pump casting 26 is interposed. The I reservoir casing attached to the base and reservoir casing surrounds the cylinder F, extending around. the vsupper "cylinder, suband acts as a brace for the said cylinder. In stantially. as described. order to lower the plunger 13, a knob 81 is 4. In combination the base, a block suspressed upon, the rod of which will unseat a pended therein and resting upon the upper 5 valve 82 and allow the oil, under the weight 1 part of the base, a cylinder attached to the of the plunger or standard B, to pass from said block, a reservoir surrounding the cylinder and supported on the upperpart of of a cylinder and piston axially below the the base, and a pump carried by. the block, upper cylinder, a reservoir surrounding the substantially as described. upper cylinder, a return port from the cyl- 5. In combination a base, a cylinder, a inder to the reservoir, a valve controlling 20 5 vertically movable plunger therein, a resersaid port, an operating rod for the valve, voir surrounding the cylinder, a pump cona casing inclosing the said rod extending up sisting of a cylinder and piston axially in from the reservoir, and a relief port c0n-' line with and below the first cylinder, a re- 'nected with the upper part of the said casturn port from the upper cylinder to the ing for the return of oil to the reservoir 25 10 surrounding reservoir, a ball valve controltherethrough, substantially as described.

ling the said port, and rod for operating In testimony whereof, I aflix my signathe valve for lowering? the plunger, substanture in presence of two Witnesses. tially as described. THOMAS MARSHALL SMITHQ 6. In combination the base, the cylinder Witnesses-z 15 extending up therefrom, a plunger movable EDWARD L. BASH,

vertically in the cylinder, a pump consisting WALTER DONALDSON. 

